Hello,
and marketing-led promotion of signature ranges, almost certainly encouraged by demand from some of the important trade buyers.
What evidence do you have for coming to that conclusion Bernard? As far as I am aware you couldn't be further from the facts. Actually, it was the trade buyers being too darn conservative that stalled the production and sales of modern cut wares in the UK. They (the trade buyers) felt comfortable with the traditional Victorian influenced designs and decided that that was what the public wanted - so that was what they bought.
In the case of cut glass, facsimile signatures were
introduced by the manufacturers as a means of promoting desirable items, noteably in conjunction with the Harrods Exhibition of 1934, "Modern Art for the Table", and in the following year at the "Art in Industry" exhibition held at the Royal Academy.
In the former there were items with designs for Stuart & Sons by: Eric Ravilious, Paul Nash, Graham Sutherland, Dame Laura Knight, Vanessa Bell, Gordon Forsythe, Moira Forsythe, Ernest Procter and Dod Procter, as well as the in-house designer Ludwig Kny.
In the latter, in addition to those from the Harrods exhibition, add Keith Murray for Royal Brierley (S&W), and Clyne Farquharson for John Walsh Walsh. There is also a known design by A.E.Morris, who designed for Edinburgh and Leith, that is signed.
Apart from the last sentence, the above information is all to be found in: "Art Deco to Post Modernism, A Legacy of British Art Deco Glass", by Benson & Hayhurst - still available (see dot org website) below.
Lastly, there are a number of items by Anna Fogelberg, for Thomas Webb, that are signed - usually these are etched or engraved rather than cut.
All these 'signed' pieces were introduced at the instigation of the various manufacturers to raise the profile of their wares and to obtain promotion. Naturally, with the Harrods exhibition, since, apart from Kny, all were invited artists, it was sensible to have their designs signed, as if imitating art, so giving the work gravitas.
The above also answers the original question, there is no evidence to date that Ravilious designed for any other glass company, but Stuart & Sons.
Nigel